Data from: Replicated evolutionary divergence in the cuticular hydrocarbon profile of male crickets associated with the loss of song in the Hawaiian archipelago

Female choice based on male secondary sexual traits is well documented, although the extent to which this selection can drive an evolutionary divergence in male traits among populations is less clear. Male field crickets Teleogryllus oceanicus attract females using a calling song and once contacted switch to courtship song to persuade them to mate. These crickets also secrete onto their cuticle a cocktail of long-chained fatty acids or cuticular hydrocarbons (CHCs). Females choose among potential mates based on the structure of male acoustic signals and on the composition of male CHC profiles. Here, we utilize two naturally occurring mutations that have arisen independently on two Hawaiian islands and render the male silent to ask whether the evolutionary loss of acoustic signalling can drive an evolutionary divergence in the alternative signalling modality, male CHC profiles. QST-FST comparisons revealed strong patterns of CHC divergence among three populations of crickets on the islands of Hawaii, Oahu and Kauai. Contrasts between wild-type and flatwing males on the islands of Oahu and Kauai indicated that variation in male CHC profiles within populations is associated with the loss of acoustic signalling; flatwing males had a relatively low abundance of long-chained CHCs relative to the short-chained CHCs that females find attractive. Given their dual functions in desiccation resistance and sexual signalling, insect CHCs may be particularly important traits for reproductive isolation and ultimately speciation.

基于雄性第二性征的雌性配偶选择已有充分的文献记载，尽管这类选择压力在多大程度上能够推动不同种群间雄性性状的演化分化，目前仍尚无定论。雄性田野蟋蟀（Teleogryllus oceanicus）通过鸣唱声吸引雌性，在雌性接触后则转换为求偶鸣唱以促成交配。这类蟋蟀还会在表皮分泌长链脂肪酸混合物，即表皮碳氢化合物（cuticular hydrocarbons, CHCs）。雌性会依据雄性的声学信号结构以及雄性表皮碳氢化合物的组分来选择配偶。本研究利用两个分别在夏威夷两座岛屿上独立演化出的自然突变体——这类突变会使雄性丧失鸣唱能力——以探究声学信号的演化丢失是否会推动另一信号模式（即雄性表皮碳氢化合物组分）的演化分化。QST-FST对比分析显示，夏威夷岛、瓦胡岛与考爱岛的三个蟋蟀种群间存在显著的表皮碳氢化合物分化模式。对瓦胡岛和考爱岛上的野生型与平翅型（flatwing）雄性的对比分析表明，种群内雄性表皮碳氢化合物组分的变异与声学信号的丢失相关；相较于雌性偏好的短链表皮碳氢化合物，平翅型雄性的长链表皮碳氢化合物丰度相对较低。鉴于昆虫表皮碳氢化合物兼具抗脱水与性信号传导的双重功能，这类物质或为生殖隔离乃至最终物种形成过程中的关键性状。